In recent years the substructure of flat roofs, which formerly were covered with tar paper and asphalt, have been replaced by gravel-ballasted, waterproof, rubber membranes and the like, which are easier to install and more durable. Various edge systems, as exemplified in the following prior arts patents, have been proposed for fastening the membranes at the edges of the roof in a manner to avoid piercing the membrane edges, such that the membrane is rendered non-waterproof and subject to tear:
______________________________________ 4,071,987 Hickman 4,439,956 House 4,155,203 Wolma 4,472,913 Hickman 4,241,549 Hall et al 4,483,112 Rueblinger 4,403,458 Lolley 4,549,376 Hickman 4,419,850 Butzen 4,549,377 Castle 4,598,507 Hickman ______________________________________
Particularly in some areas of the country, wind conditions are often extreme, and it is difficult to keep a membrane in place in view of the tremendous pressures which are generated when air pressures build up under the membrane and tend to lift the membrane, even when the membrane is severely ballasted. The prior art is replete with various prior art systems which have been proposed to solve the problem of securing the edges of the membrane in an attractive and inexpensive manner, without perforating the membrane. Because the edges of the membrane cannot be ballasted, and are subject to the same wind lift conditions, it is, normally the edges of the membrane which, in prior art systems, are torn loose initially by wind lift conditions.